Frontend Admin by DynamiApps CVE-2026-6226: Brief Summary of Unauthenticated Privilege Escalation via Form Configuration Injection

Introduction

A newly disclosed vulnerability in the Frontend Admin by DynamiApps WordPress plugin allows unauthenticated attackers to create administrator accounts by injecting a crafted form configuration into the plugin's submission pipeline. In effect, the plugin's own form-processing logic is turned against itself. With a CVSS score of 8.8 and a trivially low exploitation barrier, this flaw is a serious risk for any WordPress site running the affected plugin.

Frontend Admin by DynamiApps (plugin slug: acf-frontend-form-element) is a WordPress plugin that lets site owners display admin forms on the frontend, so clients and users can edit content without accessing the WordPress dashboard. The plugin is hosted on the official WordPress.org repository and, based on Wordfence's bug bounty tier structure, likely has 30,000 or more active installations. It fills a niche in the WordPress ecosystem for sites that need frontend content management workflows, particularly those built with Advanced Custom Fields (ACF) and Elementor.

Technical Information

CVE-2026-6226 is classified under CWE-269 (Improper Privilege Management) and carries a CVSS v3.1 vector of CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H, for a score of 8.8. The scoring contains a discrepancy. The vulnerability description explicitly calls the flaw "unauthenticated," which would correspond to PR:N and a score of 9.8. The PR:L designation may reflect an assessment that some minimal WordPress context (such as a nonce or session state) is needed, or it may simply be a scoring inconsistency. Organizations should treat this as at least an 8.8 and potentially a 9.8 risk, depending on their deployment.

Root Cause

The core design error is that the plugin trusts user input to define the form schema. Rather than loading form definitions only from the server-side database, it accepts and processes form configuration data directly from $_POST['_acf_form'] when that value is submitted as an array. Configuration data must come from a trusted source, not from user-controllable request parameters, and this design breaks that principle.

Attack Chain

Exploitation proceeds in four stages, each in a different source file of the plugin.

Stage 1: Form Definition Injection (submit.php, line 124)

The form submission handler reads $_POST['_acf_form'] to identify which form to process. Normally this value is a scalar form ID (an integer), and the validate_form() function looks up the legitimate form configuration in the database. When an attacker submits $_POST['_acf_form'] as an array instead of a form ID, though, the validate_form() function in display.php (line 245) skips the database lookup entirely and processes the attacker-supplied array directly as the form definition.

Stage 2: Record Data Preservation (display.php, line 245)

After the spoofed form passes validation, the create_record() function keeps any attacker-supplied record data present in the submission. It does not build the record solely from trusted server-side configuration. It accepts the attacker's data and carries it forward.

Stage 3: Field Definition Fallback (user.php, line 458)

When the user action's run() function looks for field definitions to process and cannot find legitimate ones in the database, it falls back to the attacker-controlled $form['fields'] array from the injected form structure. At this point, the attacker effectively controls the entire field schema the plugin uses to process the submission.

Stage 4: Role Options Spoofing (class-role.php, line 107)

The role field's pre_update_value() validation function reads $field['role_options'] from the field definition to determine which roles may be assigned. Because the attacker controls the entire field definition through the injected form, they can set $field['role_options'] to ['administrator'], and the security check then treats the administrator role as an allowed option. The attacker submits a role value of administrator, the spoofed validation accepts it, and the plugin creates a new administrator account.

Key Source Code Files

Each stage compounds the trust violation. The plugin never verifies that the form definition came from the database, never validates that field definitions are legitimate, and never independently checks whether the site's configuration actually permits the requested role. The result is a complete authorization bypass from a single crafted POST request.

Affected Systems and Versions

All versions of the Frontend Admin by DynamiApps plugin (slug: acf-frontend-form-element) up to and including version 3.29.2 are vulnerable. Version 3.29.3 contains the fix, as documented in Changeset 3525193.

Any WordPress site running the affected plugin versions with frontend form functionality enabled is at risk. The vulnerability needs no specific configuration beyond the plugin being active. The default form submission endpoint is enough for exploitation.

Vendor Security History

The Frontend Admin plugin has a well-documented pattern of authorization failures. The Wordfence vulnerability database lists at least six distinct vulnerability entries for this plugin:

OpenCVE also lists a vulnerability involving improper missing encryption exception handling on the fea_encrypt function.

This history shows each patch addressing a specific symptom rather than the underlying design flaw, which is trusting client-supplied data for configuration and authorization decisions. Multiple critical and high-severity privilege escalation vulnerabilities in 2026 alone suggest that the plugin's architecture has not undergone a comprehensive security review. Organizations relying on this plugin should factor this track record into their risk assessment and consider whether alternative solutions with stronger security postures are available.

References

• Wordfence Advisory: Frontend Admin by DynamiApps <= 3.29.2 Unauthenticated Privilege Escalation via Form Configuration Injection
• CVE Record: CVE-2026-6226
• NVD: CVE-2026-6228 (Related Vulnerability)
• Changeset 3525193: Patch for acf-frontend-form-element
• Source: class-role.php (tag 3.28.33)
• Source: user.php (tag 3.28.33)
• Source: display.php (tag 3.28.33)
• Source: submit.php (tag 3.28.33)
• Source: class-role.php (trunk)
• Source: user.php (trunk)
• Source: display.php (trunk)
• Source: submit.php (trunk)
• Wordfence Vulnerability Database: Frontend Admin by DynamiApps
• WordPress.org Plugin Page: Frontend Admin by DynamiApps
• DynamiApps: Frontend Admin Product Page
• Patchstack: Frontend Admin Vulnerability Disclosure Program
• OpenCVE: Frontend Admin CVEs and Security Vulnerabilities
• wp-firewall.com: DynamiApps Frontend Admin Privilege Escalation Alert (CVE-2026-6228)
• VulnCheck: State of Exploitation 2026